All Automotive A/C systems incorporate either an A/C Receiver Drier or an A/C Accumulator. Both A/C Receiver Driers and A/C Accumulators act as filters that remove any debris and moisture from the Air Conditioning system. Accumulators are always located on the Low-Side of the A/C system that uses an Orifice Tube, whereas Receiver Driers reside on the High-Side and accommodate an Expansion Valve. When replacing an AC Compressor, or if opening the A/C System up for any reason, it is important to replace both the Receiver Drier and Expansion Valve or the Accumulator and Orifice Tube; doing so validates your AC Compressor Warranty.